MAK
This may come a bit late for you, but a great place to land in Germany is Siegerland, EDGS
http://www.siegerland-airport.de/index_e.htm This sits off the south-eastern tip of the Dusseldorf control zone.
Friendly, efficient - the fuel guys have been made deputy sheriffs and check your passports if you're coming from the UK! Btw, if this is what you do, give them a call on the phone first. Restaurant serves (or at least did - haven't been in a while) fab Argentinian steaks and the tower is extremely helpful with wx and route planning. Highly recommended.
Further along, Vilshofen EDMV is a nice place to visit, right on the banks of the Danube. Beware their operating hours, though! They close at 1900L even in summer. Nearly had to leave my Weisswurst on the plate there recently ;-)
There is also a bit of a German specialty other than sausages when it comes to squawk codes: if you have not been assigned a discreet squawk, you select 0021 for VFR below 5000 ft and 0022 above 5000 ft. Also, coming from Belgium or France you will be talking to Langen Info, they are the - very helpful - controlling agency covering most of the western portion of the country.
Have a great trip!